ENH: Merge precision fixes from Marcus.

Charts/vtkAxis.cxx

@@ -29,7 +29,7 @@
 #include "math.h"
 
 //-----------------------------------------------------------------------------
-vtkCxxRevisionMacro(vtkAxis, "1.20.4.3");
+vtkCxxRevisionMacro(vtkAxis, "1.20.4.4");
 
 //-----------------------------------------------------------------------------
 vtkStandardNewMacro(vtkAxis);
@@ -62,7 +62,7 @@ vtkAxis::vtkAxis()
   this->GridVisible = true;
   this->LabelsVisible = true;
   this->Precision = 2;
-  this->Notation = 2; // Fixed - do the right thing...
+  this->Notation = 0; // Mixed - do the right thing...
   this->Behavior = 0;
   this->Pen = vtkPen::New();
   this->Pen->SetColor(0, 0, 0);
@@ -118,6 +118,7 @@ void vtkAxis::Update()
       }
     }
 
+  // Figure out the scaling and origin for the scene
   double scaling = 0.0;
   double origin = 0.0;
   if (this->Point1[0] == this->Point2[0]) // x1 == x2, therefore vertical
@@ -332,6 +333,30 @@ void vtkAxis::SetRange(double minimum, double maximum)
   this->SetMaximum(maximum);
 }
 
+//-----------------------------------------------------------------------------
+void vtkAxis::SetPrecision(int precision)
+{
+  if (this->Precision == precision)
+    {
+    return;
+    }
+  this->Precision = precision;
+  this->TickMarksDirty = true;
+  this->Modified();
+}
+
+//-----------------------------------------------------------------------------
+void vtkAxis::SetNotation(int notation)
+{
+  if (this->Notation == notation)
+    {
+    return;
+    }
+  this->Notation = notation;
+  this->TickMarksDirty = true;
+  this->Modified();
+}
+
 //-----------------------------------------------------------------------------
 void vtkAxis::AutoScale()
 {
@@ -462,6 +487,12 @@ double vtkAxis::CalculateNiceMinMax(double &min, double &max)
     this->Minimum *= 0.95;
     this->Maximum *= 1.05;
     }
+  else if ((this->Maximum - this->Minimum) < 1.0e-20)
+    {
+    this->Minimum *= 0.95;
+    this->Maximum *= 1.05;
+    }
+
   double range = this->Maximum - this->Minimum;
   bool isNegative = false;
   if (range < 0.0f)

Charts/vtkAxis.h

@@ -136,12 +136,12 @@ public:
 
   // Description:
   // Get/set the numerical precision to use, default is 2.
-  vtkSetMacro(Precision, int);
+  virtual void SetPrecision(int precision);
   vtkGetMacro(Precision, int);
 
   // Description:
   // Get/set the numerical notation, standard, scientific or mixed (0, 1, 2).
-  vtkSetMacro(Notation, int);
+  virtual void SetNotation(int notation);
   vtkGetMacro(Notation, int);
 
   // Description: